1. Field of the Invention
This invention relates to a recording and/or reproducing apparatus, and more particularly a head control mechanism arranged to change a recording or reproducing position on a flexible record bearing medium by shifting a recording and/or reproducing head along the recording surface of the record bearing medium with a head shifting device.
2. Description of the Prior Art
There have been known various apparatuses of the kind for recording and/or reproducing information via a magnetic head onto a disc-shaped flexible magnetic sheet which is employed as a record bearing medium.
In the magnetic recording and/or reproducing apparatus of the above-stated kind, contact between the magnetic sheet and the magnetic head plays an important role. The term "contact" as used herein includes a case where the magnetic sheet and the magnetic head confront each other across a thin layer of air developed by the rotation of the sheet. Inadequate contact of the sheet and the head causes a loss called a "spacing loss", which hinders recording or reproduction on or from the magnetic sheet. The degradation of the recording or reproducing condition due to the spacing loss is attributable much to the deformation of the magnetic sheet as well as a scar or dust on the magnetic sheet. In the event of deformation of the magnetic sheet, not only the deformed part of the sheet is affected thereby, but also the whole magnetic sheet sometimes vibrates during its rotation. If the vibration excessively takes place during the rotation, the magnetic head might be damaged in addition to a drop in the input or output level of the apparatus during a recording or reproducing operation.
The deformation of the magnetic sheet is not only caused by an external force, such as touching of a finger, but also takes place when the magnetic head and the sheet are left in contact with each other over an excessively long period of time with the recording and/or reproducing apparatus loaded with the sheet and stopped its operation. In the event of excessively long contact, the sheet might stick to the head to damage both of them when the sheet begins to rotate under such a condition.
To prevent such deformation of the magnetic sheet or sticking between the sheet and the head, there has been proposed an apparatus which is arranged to bring the magnetic sheet and the magnetic head into contact with each other only at the time of recording or reproduction. This arrangement not only prevents the above-stated troubles but also lengthens the serviceable lives of the magnetic sheet and the magnetic head. While this arrangement is very effective for the solution of the problems of deformation, etc., of the magnetic sheet, the recording and/or reproducing apparatus of this type uses an additional drive source such as a plunger or the like for effecting change-over between the contact and non-contact states of the magnetic sheet and the magnetic head. This causes an increase in size of the whole apparatus. Besides, the drive source results in additional energy consumption and also necessitates complex sequence control during recording or reproduction.
Therefore, the above-stated arrangement using an additional drive source for change-over between contact and non-contact states of the magnetic sheet and the magnetic head is not suited for a portable and compact magnetic recording and/or reproducing apparatus such as a magnetic recording camera that must be small in size with reduced energy consumption.